How To Round Numbers To 2 Decimal Places In Python?

In this tutorial, I will explain how to round numbers to 2 decimal places in Python. As a data scientist working for a US-based company, I often need to present financial data in reports in which I had a requirement to round numbers to 2 decimal places to make the data more readable. Let’s get into the various methods to achieve this in Python with examples and screenshots of executed example code.

Table of Contents

Round Numbers to 2 Decimal Places in Python

Python provides several ways to achieve this task. Let us see some important methods.

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Method 1. Use round() Function

Python provides a built-in function round() that allows you to round a floating-point number to a specified number of decimal places. The syntax is as follows:

round(number, decimal_places)

For example, let’s say, John a sales manager in New York, wants to round the sales figure $1234.5678 to 2 decimal places:

sales = 1234.5678
rounded_sales = round(sales, 2)
print(rounded_sales)

Output:

1234.57

I have executed the above example code and added the screenshot below.

Round Numbers to 2 Decimal Places in Python

The round() function is simple to use. However, it’s important to note that it rounds the number based on the second decimal place. If the second decimal place is 5 or higher, it rounds up; otherwise, it rounds down.

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Method 2. Use f-strings

In Python 3.6 and above, you can use f-strings (formatted string literals) to round numbers to 2 decimal places. Here’s an example:

revenue = 98765.4321
print(f"The company's revenue is ${revenue:.2f}")

Output:

The company's revenue is $98765.43

I have executed the above example code and added the screenshot below.

How to Round Numbers to 2 Decimal Places in Python

In this example, .2f inside the f-string specifies that the number should be rounded to 2 decimal places and displayed as a fixed-point number.

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Method 3. Use math.floor()

If you specifically want to round down to 2 decimal places, you can use the math.floor() function in combination with multiplication and division. Here’s how it works:

import math

expenses = 5432.1987
rounded_down_expenses = math.floor(expenses * 100) / 100
print(rounded_down_expenses)

Output:

5432.19

I have executed the above example code and added the screenshot below.

Round Numbers to 2 Decimal Places in Python math.floor()

In this example, we multiply the number by 100 to shift the decimal places to the right, apply the math.floor() function to round down to the nearest integer, and then divide by 100 to shift the decimal places back.

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Method 4. Round with Decimal Module

Python’s decimal module provides support for decimal floating-point arithmetic. It offers more precise control over rounding behavior. Here’s an example:

from decimal import Decimal, ROUND_HALF_UP

profit = Decimal('7890.1234')
rounded_profit = profit.quantize(Decimal('0.01'), rounding=ROUND_HALF_UP)
print(rounded_profit)

Output:

7890.12

In this example, we create a Decimal object from a string and use the quantize() method to round it to 2 decimal places. The rounding parameter is set to ROUND_HALF_UP , which rounds numbers ending in 5 up (away from zero).

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Method 5. Format with printf-style

Python also supports printf-style formatting using the % operator. Here’s an example of rounding a number to 2 decimal places using this method:

total_assets = 1234567.8901
print("The company's total assets are $%.2f" % total_assets)

Output:

The company's total assets are $1234567.89

The %.2f format specifier indicates that the number should be displayed as a floating-point number with 2 decimal places.

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Example

Let’s consider a real-world scenario where rounding numbers to 2 decimal places is important. Sarah, a financial analyst in Los Angeles, is preparing a budget report for her company. She has a list of expenses that need to be rounded to 2 decimal places for presentation purposes.

expenses = [1234.5678, 987.6543, 2345.6789, 6789.1234]

rounded_expenses = [round(expense, 2) for expense in expenses]
print(rounded_expenses)

Output:

[1234.57, 987.65, 2345.68, 6789.12]

In this example, we use a list comprehension to iterate over the expenses list and apply the round() function to each expense, rounding it to 2 decimal places. The resulting rounded_expenses list contains the expenses rounded to 2 decimal places, ready for Sarah to include in her budget report.

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Conclusion

In this tutorial, I have explained how to round numbers to 2 decimal places in Python. I covered the round() method, f-string , math.floor(), decimal module and formatting with printf-style. We also discussed a real-time example.